1. Field of the Invention
The present invention relates to a prober and probe testing method which test an object to be tested generally arranged on a wafer-like substrate under temperature control and, more particularly, to a prober and probe testing method that test the electrical characteristics of an object to be tested more accurately.
2. Description of the Related Art
When the electrical characteristics of an integrated circuit, a liquid crystal display, or the like arranged on a wafer-like substrate (to be referred to as a “wafer” hereinafter) such as a silicon substrate are to be tested, a prober is used. As shown in FIG. 13, a conventional prober has a probe card 14, a plurality of probes 26 provided on the probe card, a main chuck 6 to receive a wafer W thereon, a moving mechanism 12 to move the main chuck in X, Y, Z, and θ directions, upper and lower cameras 39 and 38 to align the object to be tested with the probe card, a test head TH, a tester T, and the like. The main chuck 6 has a holding mechanism which can be moved three-dimensionally by the moving mechanism 12 and which holds the wafer W.
Some main chuck 6 of the prober can control the temperature of the object to be tested which is to be measured to a predetermined temperature. With this control, temperature conditions for measurement can be changed. Hence, the test is performed in an environment similar to that where the object to be tested is to be actually used. As such a prober, patent reference 1 discloses an apparatus that controls the temperature of a heating resistor provided in a main chuck on the basis of the temperature of the main chuck detected by a temperature detecting means provided at the center of the main chuck. According to patent reference 1, this test can be performed at a highly accurate temperature by controlling the temperatures of the heating resistor divided into a plurality of zones.
Patent reference 2 discloses an apparatus that includes the stage surface of a main chuck divided into a plurality of regions, grooves respectively formed in the divisional regions, supply/discharge channels open to the grooves, a supply source, switchably connected to the supply/discharge channels, of a fluid having high thermal conductivity, and an evacuation means. This prober has a structure which performs heat exchange by supplying a fluid having high thermal conductivity and chucks and holds a wafer by vacuum.
In the above prober, a comparatively large area of the main chuck is heated or cooled. It is accordingly difficult to control the temperature of each object to be tested separately. This prober has a high energy consumption. This prober also takes a long time for temperature control.
Usually, in a test using probes, probes apply a high needle pressure to a wafer placed on a main chuck. In the conventional prober, when testing an object to be tested which is arranged on the periphery of a wafer, the main chuck 6 tilts because of the needle pressure as exaggeratedly indicated by the alternate long- and short-dashed line in FIG. 14, so that a probe may not come into contact with a predetermined position on the wafer.
[Patent Reference 1]
Jpn. Pat. Appln. KOKAI Publication No. 9-186112
[Patent Reference 2]
Jpn. Pat. Appln. KOKAI Publication No. 2001-230308